Power control of network part transmitter in radio system

ABSTRACT

An apparatus, method, and computer-readable medium in various embodiments includes a transmitter that establishes a radio connection that sends signals to a user equipment using a required transmission power; a receiver that receives a signal sent by the user equipment over the radio connection, the signal comprising at least one power control command determined by the user equipment; and a processor configured to specify the required transmission power in the transmitter using a delay requirement of a service to be transferred over the radio connection and the at least one power control command as a basis for making the power control decision, wherein at least one dedicated physical channel and at least a part of a shared physical channel that is time-divisionally shared are allocated to the user equipment on the radio connection, wherein the processor is further configured to carry out the power control of the time-divisionally shared physical channel on the basis of the power control decision of the dedicated physical channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation under 35 U.S.C. §120 of co-pendingU.S. application Ser. No. 10/012,048, filed on Dec. 11, 2001.Application No. 10/012,048 is a Continuation under 35 U.S.C. § 120 ofInternational Application PCT/F100/00509, filed on Jun. 7, 2000.International Application PCT/F100/00509 claims priority to FinnishApplication No. 991351, filed on Jun. 11, 1999. The entire contents ofeach of these applications are incorporated herein by reference.

BACKGROUND

This disclosure relates to a method for performing power control of anetwork part transmitter in a radio system and a network part in theradio system using the method.

Code Division Multiple Access (CDMA) radio systems employ two types ofpower control, uplink power control and downlink power control. Theuplink power control solves what is known as the near-far effect, i.e. asituation in which the transmission of a user equipment located far fromthe base station fades under the transmission of a user equipment nearthe base station if no power control is used.

The present disclosure relates to downlink power control, where powercontrol is needed to reduce multi-user interference, or to reduceinterference caused to other cells, and to compensate the interferencecaused by other cells.

For example, IS-95 radio system uses slow power control. The system ismainly intended for speech transmission. The base station periodicallyreduces the power control employed. A user equipment measures a frameerror ratio and when the frame error ratio exceeds a predeterminedlimit, for example one percent, the user equipment requests for moretransmission power from the base station. The power control is carriedout at approximately 15 to 20 millisecond intervals (the frequency being50 to 67 Hz), and the dynamic power control range is plus/minus sixdecibels.

More recent CDMA systems, such as the cdma2000 system or the WCDMAsystem, also use fast power control, and the power control can becarried out individually for each slot of the frame, and the dynamicpower control range is fairly large. The frequency of fast power controlis, for example, 800 Hz or 1600 Hz.

In recent mobile systems data is transferred in addition to speech, butthe power control is not optimized in any way according to therequirements the services to be transferred set for the power control.

SUMMARY

It is an object of the disclosure to provide a method and an apparatusimplementing the method, in which the power control of a transmitter isoptimally implemented regarding the different services to be transferredover a radio connection. This is achieved with the method describedbelow. The method concerned refers to a method for performing powercontrol of a network part transmitter in a radio system, comprising thesteps of establishing a radio connection from the network parttransmitter to a user equipment, sending a signal on the radioconnection from the network part transmitter using the transmissionpower required, receiving the signal in the user equipment, measuring aquality value for the signal and determining a power control commandbased on the quality value, signaling the power control command from theuser equipment to the transmitter. The method comprises the steps ofspecifying the power control required in the transmitter using a delayrequirement of a service to be transferred over the radio connection andat least one received power control command as the basis for making apower control decision, continuing to perform the method from the secondoperation, i.e. sending a signal on the radio connection from thenetwork part transmitter using the transmission power required.

The disclosure also relates to a network part of a radio systemcomprising a transmitter for establishing a radio connection to a userequipment, the radio connection being formed of signals, which aretransmitted using the transmission power required, a receiver forreceiving on a radio connection a signal sent by the user equipment, thesignal comprising a power control command determined by the userequipment. The network part further comprises decision means forspecifying the transmission power required in the transmitter using adelay requirement of a service to be transferred over the radioconnection and at least one received power control command as the basisfor making a power control decision.

One aspect of the disclosure is that, according to studies carried outby the Applicant, an optimal power control method exists for eachservice to be transferred. The services to be transferred aredistinguished from one another on the basis of a delay requirementthereof. It is decided in accordance with the delay requirement howfrequently power control is actually performed. The power controlfrequency does not therefore necessarily depend on the frequency of thepower control commands to be received.

The method and the system of the disclosure provides at least such anadvantage that the downlink capacity from the network part to the userequipment increases since the average signal-to-interference ratiothereof improves.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the disclosure will be described in greater detail bymeans of various embodiments with reference to accompanying drawings, inwhich:

FIGS. 1A and 1B illustrate an example of a system of the disclosure,

FIG. 2 illustrates the operation of a transmitter and a user equipmentof the disclosure,

FIG. 3A is a flowchart showing a basic method of the disclosure,

FIGS. 3B and 3C are flowcharts complementing the basic method of thedisclosure in FIG. 3A with preferred embodiments, and

FIG. 4 illustrates an example of the structure of a frame to be used ona radio connection.

DETAILED DESCRIPTION

The disclosure can be used in all radio systems in which downlink powercontrol is required and in which different services are transferred overa radio connection. A transmission channel can be formed by means of atime division, frequency division or code division multiple accessmethod, for example. The disclosure also covers systems utilizingcombinations of different multiple access methods. The examples describehow the disclosure is used in a universal mobile telecommunicationsystem employing a wideband code division multiple access method,however, without restricting the disclosure thereto.

The structure of a universal mobile telecommunications system isdescribed below with reference to FIGS. 1A and 1B. FIG. 1B shows onlythe blocks that are essential for illustrating the disclosure, but it isobvious to those skilled in the art that a conventional mobile systemalso includes other functions and structures which do not have to bedescribed in greater detail herein. The main components of a mobilesystem are a core network CN, a UMTS terrestrial radio access networkUTRAN and a user equipment UE. The interface between the CN and theUTRAN is referred to as Iu, and the air interface between the UTRAN andthe UE is referred to as Uu.

The UTRAN consists of radio network subsystems RNS. The interfacebetween RNSs is referred to as Iur. An RNS comprises a radio networkcontroller RNC and one or more nodes B. The interface between an RNC andnode B is referred to as Iub. The coverage area of node B, i.e. a cell,is denoted in FIG. 1B by C.

The illustration in FIG. 1A is extremely abstract, and is thereforefurther clarified in FIG. 1B by showing which parts of the GSM systemand the UMTS approximately correspond to one another. It should be notedthat the mapping disclosed herein is not restrictive but onlysuggestive, since the responsibilities and functions of different partsof the UMTS are still being developed.

FIG. 1B shows packet transmission through the Internet 102 from acomputer 100 that is connected to a mobile system to a portable computer122 connected to a user equipment UE. The UE can be, for example, afixedly mounted, a vehicle-mounted or a hand-held portable terminal. Theradio network infrastructure UTRAN comprises radio network subsystemsRNS, or base station systems. An RNS includes a radio network controllerRNC, or a base station controller, and at least one node B, or basestation, controlled by the RNC.

The base station B comprises a multiplexer 114, transceivers 116 and acontrol unit 118 controlling the operation of the transceivers 116 andthe multiplexer 114. The multiplexer 114 places traffic and controlchannels used by several transceivers 116 on the transmission connectionIub.

The transceivers 116 of the base station B are connected to an antennaunit 120, which implements a bidirectional radio connection Uu to theuser equipment UE. The structure of the frames transmitted over thebidirectional radio connection Uu is accurately specified.

The base station controller RNC comprises a group switching field 110and a control unit 112. The group switching field 110 is used to switchspeech and data and to combine signaling circuits. The base stationsystem formed of the base station B and the base station controller RNCalso comprises a transcoder 108. The division of operations between thebase station controller RNC and the base station B and the physicalstructure of the elements may vary in different implementations.Typically the base station B manages the implementation of the radiopath as described above. The base station controller RNC typicallycontrols the following matters: radio resource management, control ofinter-cell handover, power control, timing and synchronization, pagingof user equipment.

The transcoder 108 is usually located as close to a mobile servicesswitching centre 106 as possible since speech can be transmitted inmobile telephone system form between the transcoder 108 and the basestation controller RNC, thus saving transmission capacity. Thetranscoder 108 adapts different digital speech coding forms used betweena public switched telephone network and a mobile telephone network toeach other, converting for example a 64 kbit/s fixed network form intosome other (such as a 13 kbit/s) form of the cellular radio network, andvice versa. The required equipment are not described in greater detailherein. However, it can be pointed out that speech is the only type ofdata that is converted in a transcoder 122. The control unit 112performs call control, mobility management, collection of statisticaldata and signalling.

The core network CN consists of the infrastructure of the mobiletelephone system outside the UTRAN. FIG. 1B shows the devices of thecore network CN, such as the mobile services switching centre 106 and agateway mobile services switching centre 104, which attends to theconnections from the mobile telephone system to the outside world, inthis case to the Internet 102.

An example of a frame structure that can be used on a physical channelis described with reference to FIG. 4. Frames 440A, 440B, 440C, 440D areconsecutively numbered from one to seventy-two, and they form a720-millisecond superframe. The length of one frame 440C is 10milliseconds. The frame 440C is divided into 16 slots 430A, 430B, 430C,430D. The length of one slot 430C is 0.625 milliseconds. One slot 430Ctypically corresponds to one power control period, during which power isadjusted, for example, by one decibel upwards or downwards.

Physical channels are divided into different types, including commonphysical channels and dedicated physical channels.

The following transport channels are carried on the common physicalchannels: PCH (Paging Channel), BCH (Broadcast channel), RACH (RandomAccess Channel) and FACH (Forward Access Channel).

Dedicated physical channels comprise dedicated physical data channels(DPDCH) 410 and dedicated physical control channels (DPCCH) 412. TheDPDCHs 410 are used to carry data 406 generated in layer two of OSI(Open Systems Interconnection) and in the layers above it, i.e.dedicated control channels. The DPCCHs 412 carry control informationgenerated in layer one of the OSI. The control information comprises:pilot bits 400 used in channel estimation, feedback information (FBI)408, transmit power control commands (TPC) 402, and optionally atransport format combination indicator (TFCI) 404. The transportcombination format indicator 404 informs the receiver about thetransport format of different transport channels, or the transportformat combination used in said frame.

As FIG. 4 shows, the downlink DPDCHs 410 and DPCCHs 412 aretime-multiplexed into the same slot 430C. In the uplink direction thechannels are, in turn, transmitted in parallel so that they areIQ/code-multiplexed (I=in-phase, Q=quadrature) into each frame 440C.

FIG. 2 illustrates a transmitter 200 of the disclosure and a userequipment UE. The Figure shows only the basic functions of the radiotransmitter 200. Different services to be placed in a physical channelinclude speech, data, moving or still video image, and system controlchannels, which are processed in a control part 208 of the radiotransmitter. The Figure only shows the data processing. Differentservices require different source coding means, for example speech callsfor a speech codec. However, for the sake of clarity the source codingmeans are not shown in FIG. 2.

Packets from the computer 100 arrive at the radio network subsystem RNSas shown in FIG. 1B, where channel coding is carried out in a channelcoder 202. The channel coding is typically convolutional coding anddifferent modifications thereof, such as turbo coding. Channel codingalso includes different block codes, such as cyclic redundancy check(CRC) and the Reed-Solomon code.

Interleaving is not shown in FIG. 2. The purpose of interleaving is tofacilitate error correction. In interleaving signal bits are mixedtogether in a particular manner, and therefore a momentary fade over theradio path does not necessarily make the transmitted informationimpossible to identify.

The signal is spread by a spreading code and modulated in a block 204.The information to be transferred in the services is multiplied by thespreading code, whereby the relatively narrowband information is spreadinto a wide frequency band. Each connection Uu has a specific spreadingcode by which the receiver identifies the transmissions intendedthereto. The pulse form of the signal obtained can be filtered. Thesignal is then modulated to a radio frequency carrier by multiplying itby a carrier. The signal obtained is ready to be sent to the radio pathUu irrespective of possible filterings and power gains.

Typically, the maximum number of mutually orthogonal spreading codessimultaneously in use is two hundred and fifty-six. For example, when a4.096 megachip carrier is used in the UMTS, the spreading factor 256corresponds to a transmission rate of thirty-two kilobits/second.Correspondingly, the highest practical transmission rate is achievedwith the spreading factor four, the data transmission rate then beingtwo thousand and forty-eight kilobits/second. The transmission rate onthe channel varies stepwise between 32, 64, 128, 256, 512, 1024 and 2048kbit/s, while the spreading factor correspondingly varies between 256,128, 64, 32, 16, 8 and 4. The transmission rate obtained by the userdepends on the channel coding used. For example, while using ⅓convolution coding the data transmission rate of the user isapproximately one third of the actual data transmission rate of thechannel. The spreading factor may indicate the length of the spreadingcode. For example the spreading code (1) corresponds with spreadingfactor one. Spreading factor two has two mutually orthogonal spreadingcodes (1,1) and (1,-1). Furthermore, spreading factor four has fourmutually orthogonal spreading codes: (1,1,1,1), (1,1,-1,-1) beneath theupper level spreading code (1,1) and spreading codes (1,-1,1,-i) and(1,-1,-1,1) beneath the upper level of the second spreading code (1,-1).The spreading codes at a certain level are generally mutuallyorthogonal, for example when using the Walsh-Hadamard code sets.

The modulated signal is supplied to radio frequency parts 210 comprisinga power amplifier 212. The radio-frequency parts 210 may also comprisefilters that restrict the bandwidth. An analogue radio signal 240 isthereafter transmitted through the antenna 214 to the radio path Uu.

The radio receiver 220 is typically a Rake receiver. An analogueradio-frequency signal 240 is received from the radio path Uu by anantenna 222. The signal 240 is supplied to radio-frequency parts 224comprising a filter which blocks frequencies outside the desiredfrequency band. The signal is thereafter converted in a demodulator 226into an intermediate frequency or directly to a baseband, in which modethe converted signal is sampled and quantized.

As the signal has propagated through several paths, themultipath-propagated signal components are preferably combined in ablock 226 comprising several Rake fingers according to the prior art.

A rowing Rake finger searches for delays for each multipath-propagatedsignal component. After locating the delays, each different Rake fingeris allocated to receive a specific multipath-propagated signalcomponent. In reception a received signal component is correlated by thespreading code used, which has been delayed by the delay located for themultipath concerned. The different demodulated and despreadmultipath-propagated components of the same signal are combined so as toobtain a stronger signal.

The signal is thereafter supplied to a channel decoder 228 decoding thechannel coding used in the transmission, for example block coding andconvolutional coding. Convolutional coding is preferably decoded by aViterbi decoder. The data obtained and originally transmitted issupplied to a computer 122 connected to the user equipment UE forfurther processing.

The quality value of the received signal is measured in a block 230. Themeasurements are associated with the channel conditions, such as channelparameters, signal reception power, bit-error rate, SINR ratio(Signal/Interference+Noise Ratio), SIR ratio (Signal/InterferenceRatio), C/I ratio (Carrier/Interference Ratio) or with any other knownmethod for measuring channel quality.

The downlink power control can be carried out, for example, so that aSIR target set by the network part is set for the connection. If theuser equipment UE detects that the SIR target set cannot be achieved,the user equipment UE signals a transmitter 232 thereof by sending apower control command to the network part RNS. The power controlcommands may indicate an absolute power value, but generally they areproportional, i.e. the power control command indicates for example thatthe power has to be adjusted by a certain amount of decibels upwards ordownwards.

The transmitter 232 of the user equipment UE sends a power controlcommand 250 to the network part RNS using an antenna 234. In the exampleshown in FIG. 4 the power control command is placed in the transmitpower control command 402 of the frame, or is transferred using theuplink DPCCH.

The network part RNS comprises a receiver 216 receiving a power controlcommand 250 sent by the user equipment UE using an antenna 218 thereof.The power control command is then processed in decision means 208 of thenetwork part RNS, in which the transmission power needed in thetransmitter 2 is specified. The power amplifier 212 is controlled tosend the signal to the user equipment UE at the desired power.

In accordance with the disclosure the decision means 208 use on a radioconnection 240 the delay requirement of the service to be transferredand at least one received power control command as the basis for thepower control decision.

The simulations carried out by the applicant show that fast downlinkpower control increases the system capacity when transferring real timeservices, such as speech. The studies made by the applicantcorrespondingly reveal that when non-real time services are transferredit is preferable for the system capacity to use slow downlink powercontrol, since the capacity can be increased by as much as 2.5 decibels.The studies made on non-real time services are published in an articleby Mika Raitola and Harri Holma: Wideband CDMA Packet Radio With HybridARQ in publication IEEE Fifth International Symposium on Spread SpectrumTechniques & Application, IEEE ISSSTA '98 Proceedings, ISBN:0-7803-4281-X, which article is incorporated herein by reference.

An example of non-real time services is packet-switched datatransmission, where a connection is established between users bytransferring data in packets that include address and controlinformation/data in addition to actual data. Packet transmissionfrequently uses a basic form or a more advanced form of an ARQ protocol.The ARQ (Automatic Repeat Request) protocol refers to a procedure inwhich the retransmission of the data to be transferred can improve thereliability of the data to be transferred by increasing the bit errorrate thereof. A more advanced form of the ARQ basic protocol is a hybridARQ, which employs a combination of the ARQ and an FEC (Forward ErrorCorrection). The FEC indicates that the data to be transferred is codedwith a coding that corrects errors, i.e. when using the terms in FIG. 2the FEC refers to channel coding that is carried out in a channel coder202.

The maximum delay of the service becomes shorter when the ARQ protocolis used together with fast power control than if the ARQ protocol isused without fast power control. One reason for this is that when thechannel fades, fast power control allows to rapidly increase thetransmission power. The use of slow power control would result inretransmitting the data. Retransmission increases time diversity, whichin turn increases capacity. The delays vary more extensively when slowpower control is used than when fast power control is used.

Let us assume that the frame error ratio of packet transmission is tenpercent after the first data transmission, and that the frame errors areuncorrelated. These assumptions are adequately valid in connection withfast power control. When slow power control is used for slow moving userequipment (the rate below 10 km/h), the frames are correlated, andlonger delays occur during channel fadings. Table 1 shows the delaydivision of packets when fast power control is used. It is assumed inthe table that each retransmission adds three frames, i.e. 30milliseconds of additional delay, and that no errors occur on thefeedback channel. TABLE 1 Number of retransmissions Probability Delay 190%  10 ms 2 10%  40 ms 3  1%  70 ms 4 0.1%  100 ms 5 10⁻⁴ 130 ms 6 10⁻⁵170 ms 7 10⁻⁶ 200 ms

The studies made be the Applicant show that the optimal E_(b)/N₀ targetusing fast power control is very narrow, whereas slow power controlprovide a very even capacity curve. The operation points of slow powercontrol can be decreased without dramatically affecting the performance.This provides flexibility for the downlink load control.

Furthermore, the studies carried out by the Applicant show that if fastpower control is not used then averagely lower transmission powers arerequired. The variations in transmission power need not be consideredeither. Slow power control sets lower requirements for the poweramplifier of the base station transmitter, since the headroom requiredby fast power control is not needed in the power amplifier. As thetransmission power on the channel generally varies, for example, fromminus three to plus three decibels, the transmission power has to beincreased up to plus fifteen decibels during channel fading, when fastpower control is used. Headroom refers to the difference in variationbetween an optimal transmission power and an average transmission power.

In the following, the operations to be performed in the power controlmethod of the disclosure are presented with reference to FIG. 3A. Theimplementation of the method starts from block 300. The radio connection240 is formed in block 302 from the network part RNS transmitter 200 tothe user equipment UE.

A signal is sent over the radio connection 240 in block 304 from thenetwork part RNS transmitter 200 using the required transmission power.In the beginning of the connection the transmission power may be adefault.

In block 306 the signal is received in the user equipment UE, and aquality value is measured for the signal in accordance with one of theabove described prior art methods. The quality value determines thepower control command, such as “add transmission power by one decibel”or “reduce transmission power by one decibel”. In block 308 the powercontrol command is signaled from the user equipment UE to the networkpart RNS transmitter.

The required transmission power needed in the transmitter is specifiedin block 310 using the delay requirement of the service to betransferred on the radio connection and at least one received powercontrol command as the basis for making the power control decision. Theoperation of this block is explained in greater detail in FIG. 3B.

In block 312 it is checked whether the radio connection 240 is still inoperation. If the radio connection does not operate any longer, then theprocess proceeds to block 314, where the method is ended. Since themethod described performs power control on one radio connection only,and since a network part transmitter 200 may simultaneously have variousconnections to different user equipment, it is obvious that the methodof the disclosure can be carried out in parallel for various connectionssimultaneously in one transmitter 200.

If the radio connection is not ended, then the process proceeds fromblock 312 to block 304, where the method is carried out from the secondoperation, i.e. the following signal is sent on the radio connection 240from the network part RNS transmitter 200 using the transmission powerrequired. Here the term “transmission power required” refers to thetransmission power specified in block 310 particularly in accordancewith the disclosure.

In the following, the operation of block 310 will be explained ingreater detail with reference to FIG. 3B. The operation of block 310 isformed of the operations of blocks 320, 322, 326 and 330.

In block 320 a choice is made according to the type of service. Whendividing the services the delay requirement thereof is the determiningfactor. The service becomes more real time the shorter the delayrequirement is.

When a short delay real time service 322 is concerned, for examplespeech transmission or short delay real time data, the process proceedsto block 324 according to which fast power control is used, and in whichthe transmission power required is specified after the reception of eachpower control command.

When a long delay real time service is concerned, for example fast delayreal time data, then the process proceeds to block 326 according towhich slower power control than the fast power control is used, and inwhich the transmission power required is not changed after each receivedpower control command. It is obvious for those skilled in the art thatthe frequency of the power control to be performed can then be arrangedto suit the nature of the data to be transferred.

When a non-real time service is concerned, such as the use of a webbrowser or one-directional data transmission, the process proceeds toblock 330, according to which slow power control is used, and in whichthe transmission power required is not changed after each received powercontrol command.

It is difficult to precisely define “fast power control”, “slower thanfast power control” and “slow power control”, since the limits thereofdepend on the radio system to be examined. However, it can be noted thatfor example in the universal mobile system the frequency of fast powercontrol is approximately 800 to 1600 Hz, i.e. the maximum power controlis performed separately for each frame slot used on the radioconnection. Correspondingly, the frequency of slow power control variesbetween 1.4 to 100 Hz, i.e. the required transmission power is changedat the most for each frame or super-frame to be used on the radioconnection. The power control which is slower than the fast powercontrol may vary between these extreme ends, or between 100 to 800 Hz.

It can be noted in this context that the disclosure can be employed insuch systems in which the signaling of a physical layer supports fastpower control only. When slower than fast power control is desired, aquantity describing an average value is calculated from a certain amountof fast power control power control commands, the quantity then beingused as a basis for making the power control decision. For example inthe universal mobile system, the value of one slow power control commandregarding one frame can be calculated from the power control commandsregarding all slots of said frame, i.e. from 16 power control commandsin all. The situation can for instance be such that nine commandsinclude the command “increase transmission power by one decibel” andseven commands include the command “reduce transmission power by onedecibel”. In such a case the command “increase transmission power by twodecibels” could be considered as an average command. Depending on thepower amplifier properties, certain limits might have to be set forpower control, since the transmission power cannot exceed a certainlimit, or be lower than a certain limit. If the power range is notsufficient then the connection is disconnected, or in the case of packettransmission a larger number of retransmissions is performed. Anotherway to solve the problem is to use handover.

FIG. 3C illustrates the effect of a service to be transferred on theerror correction strategy to be used. The measures to be carried out320, 340, 342 and 344 are included in block 304 of FIG. 3A, in which asignal to be transmitted is formed and transmitted.

In block 320 a choice is made according to the type of service.

When a short delay real time service 322 is concerned, the informationin such a service is typically protected with an error correcting FECcoding in accordance with block 340. Fast power control allows toguarantee an adequate quality for each FEC coding/interleaving sequence.

When a long delay real time service 326 is concerned, the informationincluded in the service is protected in accordance with block 342 withat least an error correcting FEC coding, and if necessaryretransmissions are implemented using an ARQ protocol. The power controlmay be slower than fast power control, since time diversity created byretransmissions can be utilized against a fading channel. The sameprocedure may be used when non-real time services are concerned, as nofixed delay requirements are set thereto, in which case random fairlylong delays can be tolerated.

The performance of non-real time services are measured in accordancewith the total performance, and not according to the delay at particulartimes. If the channel has faded but the channel conditions have notchanged, then the only way to pass the data is to adequately addtransmission power.

One way to reduce the repeated retransmissions of the same data packet,is to use soft combining of the transmitted data packets in accordancewith block 344. The soft combining can be implemented either bycombining data packets or by employing maximal ratio combining. The softcombining is disclosed in publications WO 98/49796 and WO 98/49797,which are incorporated herein by reference.

In a preferred embodiment at least one dedicated physical channel isallocated to the user equipment UE on the radio connection 240 and atleast a part of a shared physical channel that is time-divisionallyshared. In this case the downlink connection has a dedicated channelpossibly with a small transmission capacity continuously in use, and ifnecessary a shared channel in use. The shared channel is employed inbursty data transmission when a large data transmission capacity isneeded. The shared channel may have various users, and for instance atransportation format combination indicator 404 indicates who is liableto use the shared channel at a particular time. The soft combiningdescribed can also be used on a time-divisionally shared physicalchannel. The power control of the time-divisionally shared physicalchannel is carried out on the basis of the power control decision of thededicated physical channel. The power control of the shared physicalchannel is naturally user-specific.

In the radio system according to FIG. 2 the disclosure assumes that thetransmitter 200 comprises decision means 208 for specifying thetransmission power required in the transmitter 200 using the delayrequirement of the service to be transferred on the radio connection 240and at least one received power control command as the basis for thepower control decision.

The disclosure is preferably implemented by software, whereby thenetwork part RNS, for example the transmitter 200, includes amicroprocessor, in which the decision means are implemented as operatingsoftware. The disclosure can obviously also be implemented usingapparatus solutions providing the required functionality, such as theASIC (Application Specific Integrated Circuit) or as separate logic.

Even though the disclosure has been described above with reference tothe example of the accompanying drawings, it is obvious that thedisclosure is not restricted thereto but can be modified in various wayswithin the scope of the inventive idea disclosed in the attached claims.

1. An apparatus, comprising: a transmitter that establishes a radioconnection that sends signals to a user equipment using a requiredtransmission power; a receiver that receives a signal sent by the userequipment over the radio connection, the signal comprising at least onepower control command determined by the user equipment; and a processorconfigured to specify the required transmission power in the transmitterusing a delay requirement of a service to be transferred over the radioconnection and the at least one power control command as a basis formaking the power control decision, wherein at least one dedicatedphysical channel and at least a part of a shared physical channel thatis time-divisionally shared are allocated to the user equipment on theradio connection, wherein the processor is further configured to carryout the power control of the time-divisionally shared physical channelon the basis of the power control decision of the dedicated physicalchannel.
 2. The apparatus of claim 1, wherein the processor is furtherconfigured to use a fast power control for a short delay real-timeservice in which the required transmission power is specified after eachreceived power control command.
 3. The apparatus of claim 2, wherein theprocessor is further configured to protect information included in theshort delay real-time service using a forward error-correcting code. 4.The apparatus of claim 1, wherein the processor is further configured touse a slower power control than a fast power control for long delayreal-time services in which the required transmission power is notchanged after each received power control command.
 5. The apparatus ofclaim 1, wherein the processor is further configured to use a slow powercontrol for non-real time services in which the required transmissionpower is not changed after each received power control command.
 6. Theapparatus of claim 1, wherein the processor is further configured toprotect information included in the service using a forward errorcorrecting code and to determine whether a retransmission using aretransmission request protocol is necessary.
 7. The apparatus of claim6, wherein the processor is further configured to implement a softcombining of data packets retransmitted in accordance with theretransmission request protocol included in the services to reduce anumber of required retransmissions.
 8. The apparatus of claim 7, whereinat least one dedicated physical channel and at least a part of a sharedphysical channel that is time-divisionally shared are allocated to theuser equipment on the radio connection, wherein the processor is furtherconfigured to perform the soft combining of the retransmitted datapackets on the time-divisionally shared physical channel.
 9. Theapparatus of claim 1, wherein the receiver receives the power controlcommand separately for each frame slot to be used on the radioconnection.
 10. The apparatus of claim 1, wherein the processor isfurther configured to change the transmission power required lessfrequently than during each frame slot to be used on the radioconnection.
 11. The apparatus of claim 10, wherein the processor isfurther configured to change the transmission power required, at themost, during each frame to be used on the radio connection.
 12. Theapparatus of claim 10, wherein the processor is further configured tocalculate a quantity describing an average value from a certain numberof power control commands, the quantity thereafter being used as a basisfor making the power control decision.
 13. An apparatus suitable forperforming power control of a network part transmitter in a radiosystem, the apparatus comprising: means for establishing a radioconnection from the network part transmitter to a user equipment; meansfor sending a signal on the radio connection from the network parttransmitter using a required transmission power; means for receiving thesignal in the user equipment, measuring a quality value for the signaland determining a power control command based on the quality value;means for signalling the power control command from the user equipmentto the transmitter; means for specifying the power control required inthe transmitter using a delay requirement of a service to be transferredover the radio connection and at least one received power controlcommand as the basis for making a power control decision; means forallocating at least one dedicated physical channel to the user equipmenton the radio connection and at least a part of the shared physicalchannel that is time-divisionally shared; and means for carrying out thepower control of the time-divisionally shared physical channel on thebasis of the power control decision of the dedicated physical channel.14. The apparatus of claim 13, wherein short delay real time servicesuse fast power control in which the transmission power required isspecified after each received power control command.
 15. A method forpower control of a network, the method comprising: establishing a radioconnection from a network part transmitter to a user equipment; sendinga signal on the radio connection from the network part transmitter usinga required transmission power; receiving at least one power controlcommand from the user equipment, said power control command beingdetermined, at least in part, upon a quality value relating to a signalquality in the user equipment; specifying a required power control forthe transmitter using a delay requirement of a service to be transferredover the radio connection and said at least one received power controlcommand as the basis for making a power control decision, wherein atleast one dedicated physical channel is allocated to the radioconnection and at least a part of the shared physical channel that istime-divisionally shared, and the power control of the time-divisionallyshared physical channel is carried out on the basis of the power controldecision of the dedicated physical channel.
 16. A computer programproduct containing a computer-readable medium, the computer-readablemedium comprising computer code thereon suitable for performing powercontrol in a network which, when executed by a processor, causes theprocessor to: establish a radio connection from a network parttransmitter to a user equipment; send a signal on the radio connectionfrom the network part transmitter using a required transmission power;interpret a power control command received from the user equipment;specify a power control required in the transmitter using a delayrequirement of a service to be transferred over the radio connection andat least one received power control command as the basis for making apower control decision; allocate at least one dedicated physical channelto the user equipment on the radio connection and at least a part of theshared physical channel that is time-divisionally shared; and carry outthe power control of the time-divisionally shared physical channel onthe basis of the power control decision of the dedicated physicalchannel.
 17. The computer program product of claim 16, wherein thecomputer code, when executed, causes the processor to assign a fastpower control for short delay real-time services so as to specify thetransmission power required after each received power control command.